1. Field of the Invention
This invention relates to a structural arrangement for a concentric tube heat exchanger and particularly it relates to a unique support for a modular tube type heat exchanger wherein a heating fluid flowing outside the tubes thereof transmits heat to a second fluid flowing through the space between the concentric tubes.
2. Description of the Prior Art
Recuperative heat exchangers employing a series of concentric tubes are frequently used to transfer heat from hot combustion gases to cool air being supplied for combustion. The exhaust or waste gases are usually at extremely high temperatures when they enter the chamber of the heat exchanger in which the tubes are located and thus adversely affect the recuperator tubes and the housing in which they are supported. Moreover, differential expansion between tubes and housing structure damages any connection therebetween, so structural integrity of the heat exchanger is compromised and the heat exchanger is frequently forced to operate at less than maximum efficiency.
Examples of conventional heat exchange art are to be found in U.S. Pat. No. 3,586,098 and U.S. Pat. No. 2,670,945 where tube sheets supporting tubular heat exchangers are rigidly connected to inlet and outlet headers before being rigidly connected to surroundig housing structure. The temperature gradient inherent in devices of this type effects relative expansion and contraction of the several parts, and breakage of the weldments therebetween is common. Moreover, conventional heat exchangers of this type are excessively large and they frequently utilize extensive amounts of transverse ducting which may be extremely difficult to fit into exisiting space allotments.